MOBILE COMMUNICATIONS Alexandre ELAGUINE & Mikhail BAIAKOVSKI

MOBILE COMMUNICATIONS Basic principles Early analog networks Digital networks, GSM GPRS and EDGE UMTS Future networks

Wireless versus Mobile

BASIC NETWORK STRUCTURE

Propagation Mechanisms Reflection Diffraction (Shadowing) Scattering Doppler effects Fading

FREQUENCY REUSE

3/9 CELL PATTERN

BASIC NETWORK STRUCTURE

SYSTEM STRUCTURE

ANALOGUE MOBILE NETWORKS

DIGITAL MOBILE NETWORKS

SIM: SUBSCRIBER IDENTITY MODULE

GSM frequency bands 900 MHz –2*25 MHz Bands –45 MHz Duplex Spacing –125 carriers 1800 MHz –2*75 MHz Bands –95 MHz Duplex Spacing –375 carriers 1900 MHz –2*60 MHz Bands –80 MHz Duplex Spacing –300 Carriers MHz Uplink MHz Downlink MHz Uplink MHz Downlink MHz Uplink MHz Downlink

GSM: AREAS

THREE ACCESS METHODS IN CELLULAR SYSTEMS FDMA Frequency Division Multiple Access TDMA Time Division Multiple Access CDMA Code Division Multiple Access

TDMA: FRAME

D-AMPS The EIA/TIA (TDMA) standard has many names –TDMA (the most common) –US Digital Cellular (USDC) –North American TDMA (NA-TDMA) –Digital AMPS (D-AMPS) –IS-54 and IS-136

CDMA Every mobile in the network has a unique code, the chip sequence When a mobile sends a bit stream, each bit is replaced by the chip code A « one » in the bit stream is replaced by the chip code A « zero » in the bit code is replaced by the compliment of the chip code If the chip code is n bits long, each bit in the original bit stream is replaced by n bits Instead of some 10kbps in the original bit stream, Mbps is sent This is often referred as to « spread spectrum techniques »

GPRS, GENERAL PACKET RADIO SERVICE (1) Genera! Packet Radio Service (GPRS) is a new service designed for digital cellular networks (GSM, DCS, PCS). GPRS uses a packet-mode technique to transfer high-speed and tow- speed data and signalling in an efficient manner over GSM radio networks. GPRS can be used for carrying end user's packet data protocol such as IP andX.25 GPRS is standardised in ETSI (European Telecommunications StandardsInstitute). New GPRS radio channels are defined, and the allocation of these channels is flexible: from 1 to 8 radio interface timeslots can be allocated per TDMA frame, timeslots are shared by the active users, and up and downlink are allocated separately. Various radio channel coding schemes are specified to allow bitrates from 9 to more than 150 kbit/s per user.

GPRS, GENERAL PACKET RADIO SERVICE (2) GPRS introduces two new network nodes in the GSM PLMN: The Serving GPRS Support Node (SGSN), which is at the same hierarchical level as the MSC, keeps track of the individual MSs' location and performs security functions and access control. The SGSN is connected to the base station system with Frame Relay. The Gateway GSN (GGSN) provides interworking with external packet-switched networks, and is connected with SGSNs via an IP-based GPRS backbone network. The HLR is enhanced with GPRS subscriber information, and the SMS-MSCs are upgraded to support SMS transmission via the SGSN. Optionally, the MSC/VLR can be enhanced for more-efficient co-ordination of GPRS and non- GPRS services and functionality: e.g., paging for circuit- switched calls which can be performed more efficiently via the SGSN, and combined GPRS and non-GPRS location updates.

EDGE Enhanced Data rates for GSM Evolution ECSD - Enhanced CSD (Circuit Switched Data) EGPRS - Enhanced GPRS For higher data rates New coding and modulation schemes The base stations need to be up dated EGPRS up to 384 kbps (48 kbps per time slot) ECSD 28.8 kbps

IMT-2000 FPLMTS: Future Public Land Mobile Telecommunications System IMT 2000: International Mobile Telecommunications UMTS: Universal Mobile Telecommunications System UMTS: Specificed by ETSI, CEPT and UMTS forum

IMT-2000 The main characteristic of 3G Systems, known collectively as IMT- 2000, are a single family of compatible standards that have the following characteristics Used worldwide Used for all mobile applications Support both packet-switched and circuit-switched data transmission Offer high data rates up to 2Mbps (depending on mobility/velocity) Offer high spectrum efficiency

IMT-2000 IMT-2000 stands for –IMT: International Mobile Communications2000: the frequency range of 2000 MHz and the year 2000 (WARC'92: MHz and MHz) All 3G standards have been developed by regional standard developing organizations (SDOs) In total, proposals for 17 different IMT-2000 standards were submitted by regional SDOs to ITU in proposals for terrestrial systems and 6 for mobile satellite systems (MSSs). Evaluation of the proposals was completed in 1998, and negotiatians to build a consensus among different views were completed in mid All 17 proposals have been accepted by ITU as IMT-2000 standards. The specification for the Radio Transmission Technology (RTT) was released at the end of 1999.

The most important IMT-2000 proposals UMTS (W-CDMA) –as the successor of GSM CDMA2000 –universal wireless communication-13 6 (UWC- 136)/EDGE as the successor of the interim standard'95 (IS-95) time division-synchroneous CDMA (TD-CDMA) – as the TDMA-based enhancements to D- AMPS/GSM

ITU IMT2000 Radio Interface Specifications 5 were approved by the ITU in November 1999 –IMT DS Wideband CDMA (WCDMA) –IMT MC cdma 2000 –IMT SCUWC-136 (EDGE) –IMT TCUTRA TDD or TD-SCDMA –IMT FTDECT –DS: Direct Sequence, MC: Multi-Carrier, TC: Time Code, FT :Frequency Time

Key Differences between W-CDMA and cdma2000

UMTS UMTS is being developed by Third-Generation Partnership Project (3GPP), a joint venture of several SDOs –ETSI (Europe) –Association of Radio Industries and Business/Telecommunication Technology Committee (ARIB/TTC) (Japan) –American National Standards Institute (ANSI) T-1 (USA) –Telecommunications Technology Association (TTA) (South Korea) –Chinese Wireless Telecommunication Standard (CWTS) (China)

Towards UMTS

Evolutionary Concept

Maximum Data Rates